I think you might be missing the overarching issue here.
It isn't so much about the specifics of gay marriage, or Eich's donation, or him losing his job because of his opinions.
The real issue is hypocrisy, contradiction and double-standards.
We've seen one group (in this case the pro-gay-marriage crowd) act in a way towards others (Eich and the anti-gay-marriage crowd) that the first group would think is absolutely abhorrent were they the target, yet they consider perfectly acceptable when they direct it towards others.
On one hand, we've seen arguments like, "There is no right to free speech without consequences." and, "he had views that the community was overwhelmingly against" used in this very submission's discussion to justify Eich losing his job merely for expressing an opinion that may be construed as against gay marriage.
Yet imagine the uproar if somebody lost his or her job for merely expressing an opinion in favor of gay marriage, and those exact same arguments were used to justify it.
It's difficult to take people seriously when they claim to support "equality" and "tolerance", or when they claim to be against "discrimination", yet they act in a way that's completely contradictory to all of those ideals.
If one group of people is going to hold another group of people to a certain set of standards, they really should make sure that they're willing to live by that exact same set of standards, too.